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Catalytic performance of silica - supported silver nanoparticles for liquid - phase oxidation of ethylbenzene / Raji Vadakkekara in Industrial & engineering chemistry research, Vol. 51 N° 16 (Avril 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 16 (Avril 2012) . - pp. 5691-5698 Titre : Catalytic performance of silica - supported silver nanoparticles for liquid - phase oxidation of ethylbenzene Type de document : texte imprimé Auteurs : Raji Vadakkekara, Auteur ; Mousumi Chakraborty, Auteur ; Parimal A. Parikh, Auteur Année de publication : 2012 Article en page(s) : pp. 5691-5698 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Oxidation  Liquid  phase  Nanoparticle  Catalytic  reaction Résumé : In this study silver nanoparticles were prepared by chemical reduction method using silver nitrate as metal precursor, starch as protecting agent, and sodium borohydride (NaBH4) as a reducing agent. Formation of silver nanoparticles was monitored using UV-vis absorption spectroscopy and dynamic light scattering (DLS). They were supported on silica by dispersing silica powder in the suspension of destabilized silver nanoparticles. Samples containing different proportions of silver were thus prepared. This method is at variance from the conventionally employed method, i.e., impregnation of silver salt from its solution on support. Ag/SiO2 samples were characterized by UV-vis absorption spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductive coupled plasma optical emission spectroscopy (ICP-OES), and N, adsorption-desorption. Superior catalytic performance of the catalyst prepared by the present method could be observed in a test reaction of ethylbenzene oxidation affording high selectivity to acetophenone as compared to the catalyst prepared by the conventional reported methods. The 5 wt % Ag/SiO2 catalyst was found not much susceptible to sintering as could be inferred from the comparable performance of the regenerated and fresh catalysts. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25834482 [article] Catalytic performance of silica - supported silver nanoparticles for liquid - phase oxidation of ethylbenzene [texte imprimé] / Raji Vadakkekara, Auteur ; Mousumi Chakraborty, Auteur ; Parimal A. Parikh, Auteur . - 2012 . - pp. 5691-5698. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 16 (Avril 2012) . - pp. 5691-5698 Mots-clés : Oxidation  Liquid  phase  Nanoparticle  Catalytic  reaction Résumé : In this study silver nanoparticles were prepared by chemical reduction method using silver nitrate as metal precursor, starch as protecting agent, and sodium borohydride (NaBH4) as a reducing agent. Formation of silver nanoparticles was monitored using UV-vis absorption spectroscopy and dynamic light scattering (DLS). They were supported on silica by dispersing silica powder in the suspension of destabilized silver nanoparticles. Samples containing different proportions of silver were thus prepared. This method is at variance from the conventionally employed method, i.e., impregnation of silver salt from its solution on support. Ag/SiO2 samples were characterized by UV-vis absorption spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductive coupled plasma optical emission spectroscopy (ICP-OES), and N, adsorption-desorption. Superior catalytic performance of the catalyst prepared by the present method could be observed in a test reaction of ethylbenzene oxidation affording high selectivity to acetophenone as compared to the catalyst prepared by the conventional reported methods. The 5 wt % Ag/SiO2 catalyst was found not much susceptible to sintering as could be inferred from the comparable performance of the regenerated and fresh catalysts. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25834482

Evaluation of fuel properties of butanol − biodiesel − diesel blends and their impact on engine performance and emissions / Rakhi N. Mehta in Industrial & engineering chemistry research, Vol. 49 N° 16 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7660–7665 Titre : Evaluation of fuel properties of butanol − biodiesel − diesel blends and their impact on engine performance and emissions Type de document : texte imprimé Auteurs : Rakhi N. Mehta, Auteur ; Mousumi Chakraborty, Auteur ; Pinakeswar Mahanta, Auteur Année de publication : 2010 Article en page(s) : pp. 7660–7665 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Fuel  properties  Biodiesel  Engine Résumé : Present work deals with the development of butanol−diesel−biodiesel blends to substitute for petrodiesel. These blends were tested for physical stability and various fuel properties conforming to ASTM standards. Subsequently engine performance and emission tests were conducted with each blend. Observations revealed the blends to be thermally and physically stable, and they showed good resemblance to the properties of diesel, with the exception of flash point only. Brake power showed marginal decrease and fuel consumption an increase in the range of 4.9%−10.7% as compared to diesel for identical performance. Exhaust gas temperature showed a drop in the range of 3.3%−9.4% due to quenching effect of butanol, whereas brake thermal efficiency showed a reduction of 6.3%−10% to that over petrodiesel. Exhaust gas emissions showed a significant decrease in CO (42%) at medium and higher loads, whereas NO showed an average increase of 2.4%−11% as compared to diesel. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1006257 [article] Evaluation of fuel properties of butanol − biodiesel − diesel blends and their impact on engine performance and emissions [texte imprimé] / Rakhi N. Mehta, Auteur ; Mousumi Chakraborty, Auteur ; Pinakeswar Mahanta, Auteur . - 2010 . - pp. 7660–7665. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7660–7665 Mots-clés : Fuel  properties  Biodiesel  Engine Résumé : Present work deals with the development of butanol−diesel−biodiesel blends to substitute for petrodiesel. These blends were tested for physical stability and various fuel properties conforming to ASTM standards. Subsequently engine performance and emission tests were conducted with each blend. Observations revealed the blends to be thermally and physically stable, and they showed good resemblance to the properties of diesel, with the exception of flash point only. Brake power showed marginal decrease and fuel consumption an increase in the range of 4.9%−10.7% as compared to diesel for identical performance. Exhaust gas temperature showed a drop in the range of 3.3%−9.4% due to quenching effect of butanol, whereas brake thermal efficiency showed a reduction of 6.3%−10% to that over petrodiesel. Exhaust gas emissions showed a significant decrease in CO (42%) at medium and higher loads, whereas NO showed an average increase of 2.4%−11% as compared to diesel. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1006257

Formation of ruthenium nanoparticles by the mixing of two reactive microemulsions / Sachin U. Nandanwar in Industrial & engineering chemistry research, Vol. 50 N° 19 (Octobre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 19 (Octobre 2011) . - pp. 11445-11451 Titre : Formation of ruthenium nanoparticles by the mixing of two reactive microemulsions Type de document : texte imprimé Auteurs : Sachin U. Nandanwar, Auteur ; Mousumi Chakraborty, Auteur ; Z. V. P. Murthy, Auteur Année de publication : 2011 Article en page(s) : pp. 11445-11451 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microemulsion  Mixing  Nanoparticle Résumé : In this study, two reactants (ruthenium chloride and sodium borohydrate) were premicellized in two separate microemulsions and brought into contact through intermicellar exchange to conduct the reaction. As a result, ruthenium nanoparticles were formed. The overall reaction rate was governed by the intermicellar exchange rate. Particle size was controlled by varying surfactant concentration, water-to-surfactant molar ratio (ω), precursor (ruthenium chloride) concentration, and molar ratio of reducing agent-to-reagent (R). Dynamic light scattering and transmission electron microscopy were used to determine the size, size distribution, and structure of the synthesized ruthenium nanoparticles. The molar ratio ω was varied from 3 to 7; sizes of the particles were found to be in the range of 17.08―25.09 nm. The precursor (ruthenium chloride) concentration was varied in the range of 0.1―0.3 M; particle size was observed to decrease up to 0.2 M then increase due to particle agglomeration at higher precursor concentrations. Smaller nanoparticles were obtained at higher R values due to faster intramicellar nucleation and growth rate. Dispersion destabilization of colloidal ruthenium nanoparticles was detected by Turbiscan. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24573341 [article] Formation of ruthenium nanoparticles by the mixing of two reactive microemulsions [texte imprimé] / Sachin U. Nandanwar, Auteur ; Mousumi Chakraborty, Auteur ; Z. V. P. Murthy, Auteur . - 2011 . - pp. 11445-11451. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 19 (Octobre 2011) . - pp. 11445-11451 Mots-clés : Microemulsion  Mixing  Nanoparticle Résumé : In this study, two reactants (ruthenium chloride and sodium borohydrate) were premicellized in two separate microemulsions and brought into contact through intermicellar exchange to conduct the reaction. As a result, ruthenium nanoparticles were formed. The overall reaction rate was governed by the intermicellar exchange rate. Particle size was controlled by varying surfactant concentration, water-to-surfactant molar ratio (ω), precursor (ruthenium chloride) concentration, and molar ratio of reducing agent-to-reagent (R). Dynamic light scattering and transmission electron microscopy were used to determine the size, size distribution, and structure of the synthesized ruthenium nanoparticles. The molar ratio ω was varied from 3 to 7; sizes of the particles were found to be in the range of 17.08―25.09 nm. The precursor (ruthenium chloride) concentration was varied in the range of 0.1―0.3 M; particle size was observed to decrease up to 0.2 M then increase due to particle agglomeration at higher precursor concentrations. Smaller nanoparticles were obtained at higher R values due to faster intramicellar nucleation and growth rate. Dispersion destabilization of colloidal ruthenium nanoparticles was detected by Turbiscan. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24573341